Goals and Objectives: The main goal of this study is to evaluate whether use of an electronic patient portal can reduce health services utilization and improve quality of care in a population of rural, chronically ill patients. The first aim of this study is to develop a typology for describing how patients use the portal. The second aim is to describe the patient characteristics associated with different patterns of portal use. The third aim is to evaluate the effect of portal use on patient utilization and quality of care. This study is highly relevant to AHRQ's mission to increase the development, diffusion, and adoption of health information technology (HIT) to improve the quality of health care. Background: Patient portals are a new type of HIT that allow patients to securely access both their personal medical information and their healthcare provider from any Internet-connected computer. Portals may empower patients to become more involved in, and improve the outcomes of, their care. Few studies of portals have been conducted. Methods/Data Sources: This study is a secondary analysis of data being collected by Geisinger Health System (GHS), an integrated delivery system serving rural Pennsylvania, as part of GHS's ongoing study of a portal-based intervention to improve the care of chronically ill patients. Data from approximately 2,000 users in the intervention arm and 2,000 users in the control arm of the GHS study will be available for comparison with 2,000 non-users of the portal. Comprehensive patient data and encounter information will be available from GHS's electronic health record. A telephone survey previously conducted by GHS will provide detailed information on additional patient-level variables, including patient activation and Internet use, for a subset of 200 users from each arm of the GHS study. The first aim will use log-file analysis and factor analysis models to develop a typology of portal use. The second aim will use regression models to describe the association between portal usage patterns and patient characteristics. The third aim will use regression models to describe the association between portal use and utilization and clinical outcomes. Significance: This study will provide some of the first evidence of the potential for patient-centered HIT to improve chronic disease care, a significant public health issue requiring new approaches and tools. In addition, this study addresses a rural and a chronically ill population, both of which AHRQ has identified as priority populations. [unreadable] [unreadable] [unreadable] [unreadable]